How to change username to Prefered Name (display name) on vb 4.0.x

[pinkbeat]

Hi all

I'm a newbie and deployed 1 forum using vBulletin version 4.0.2. Everything is ok, but I have a problem with change username show on the left along with the post, exp: i want to change "ducnm" = "Nguyen Minh Duc". please help me?

thanks all

[TheSupportForum]

/admincp/user.php?do=modify

click search for all users, select the user, then you can edit their username